Time delay actuator having a filter element



June 1, 1965 F. v. MlNGRoNE 3,187,121

.TIME DELAY ACTUATOR HAVING A FILTER ELEMENT Filed OCb. 16, 1961 INVENTOR. Y FRANK V. MINGRONE ATTORNEYS.

United States Patent O 3,187,121 TIME DELAY ACTUATOR HAVING A FILTER ELEMENT Frank V. Mingrone, Milford, Conn., assigner to Robertshaw Controls Company, Richmond, Va., a corporation of Delaware Filed Oct. 16, 1961, Ser. No. 145,302 2 Claims. (Cl. 200-34) This invention relates to devices for automatically controlling the actuation of an electric switch or other control device and particularly to appanatus of the type in which a desired event such as t-he opening or closing of an electric circuit is accomplished after a predetermined time interval following actuation of the apparatus by some automatic means.

It is an object of this invention to effect the return movement of an actuator of an electric switch or other control device to a predetermined position after a time delay interval following dis-placement of the actuator `from the predetermined position.

Another object is to provide a time delay actuator in which the time delay interval may be quickly adjusted in accordance with va-rying conditions.

Another object is to provide a time delay device which is simple in construction, having a minimum number of parts and which is economical to produce.

In attaining the objects of t-he invention, a resilient bellows is provided with a threaded opening in one end wall. Loosely threaded into the opening is a screw, and va compressible filter element is disposed between the head of the screw and end of the bel-lows so that fluid flowing to and from the interior of the bellows passes through the filter element and between the threads of the screw and the threaded opening. Rotation of the screw increases and decreases the `density of the filter element and hence the rate at which fluid will flow into and out of the bellows. Compression of the bellows causes the fluid to be expelled from the interior and thereafter, the inherent resiliency of the bellows causes it to expand by drawing fluid through the filter and threaded opening. Adjustment of the rate of expansion of the bellows is accomplished by rotation of the screw to vary the density of the filter.

Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawings in which:

yFIG. l is a -front View of the device partially in section;

lFIG. 2 is a side view;

FIG. 3 is a view similar to FIG. l with the bellows contracted; and

iFIG. 4 is an enlarged detail of the device.

With reference to the drawings, a support or frame 1) comprises upper and lower walls 12 and 16 connected by a vertical wall 14. For mounting the frame on a wall or other supporting structure, a leg portion 18 is provided having slots 20 formed therein for receiving suitable fastening devices. Formed on the upper wall 16 is a pair of depend-ing arms 24 `for a purpose to be described below. Mounted on top of the upper wall 16 is a switch or other control device 26 having an operating plunger 2S which extends through opening 22 in wall 16. Switch 26 may be of any conventional design and may be of the type in which the switch is open when plunger 28 is released, as illustrated in FIG. 3; and when plunger 28 is held in the position shown in FIG. l, the switch is closed.

Pivotally mounted on :arms 24 is a lever 3l) having a pair of depending ears 32 which are received between arms 24 and are pivotally mounted thereon by a pivot pin 34. Lever has a depending angular portion 36 at its free end with a curved portion 38 for engagement with a cam 40. Gam 40 is assumed to be part of the apparatus controlled by actuation of switch 26. However, it should be understood that means other than cam 40 may be utilized to actuate lever 30.

Lever 3i) has a rivet 42 mounted in its .opposite end from curved portion 38 which is provided with a spherical head portion 44. When lever Sil is in the position shown in FIG. l, rivet 4t2 engages plunger 23 of switch 26 and maintains it in its upper posit-ion. This position is the predetermined position in which it is desired to return the plunger after actuation of the apparatus by ca-m 40.

Mounted on lower wall 12 of support 10 is a hollow resilient bellows 46, preferably of metal. The `free end of bellows 45 comprises a closed end wall 48 having a hemispherical depression Sil formed therein for receiving the head 44 of rivet 4t2. Bellows 46 is connected at its other end with a bellows head 52 by conventional means such as welding or soldering. Formed in bellows head 42 is a threaded opening 54 (see FIG. 4). Lower wall I2 of support 1o has an opening 5o formed therein which is coaxial- -ly disposed with respect to the opening 22 in upper wall 16.

For securing the bellows 46 to wall 12 `a screw 58 having a flanged head portion 6l) is threadedly received in opening 54 of bellows head 52. The tolerance between the threads on sere-w 53 and the threads of opening 54 in bellows head 52 is such that a-ir or other fluid may flow between the threads of the screw.

Disposed between the bellows head 52 and wall 12 of support 1li is an annular gasket 62 of rubber or other resilient material for providing a fluid tight seal between the parts. Disposed between the yflanged head portion of) of screw 5S is a porous filter 64 of compressible material such as ceramic or glass felt. Filter element 64 is illustrated as being in the form of an annular washer. The outer diameter of filter 64 is larger than the outer `diameter of the flanged head portion 69 of screw 5S; and accordingly, the peripheral portion of filter element 64 is uncontined between wall 12 and head portion 6d of screw Sd.

With the above described construction, rotation of screw 5S increases and decreases the compression on filter element 64 and thus the density thereof. This in turn varies the resistance of fluid flow through filter element 64. Rotation of screw 58 also compresses gasket 62 to provide the fluid tight seal between the bellows head 52 and wall 12 so that the only path of fluid flow from the interior of bellows 45 to the exterior thereof is through the threaded opening 54, opening 56 in wall 12, and filter element 64.

In operation, bellows 46 is illustrated in its normal extended position in FIG. 1 and is maintained in this position by the inherent bias of the bellows material. Head portion 44 of rivet 42 `at the end of lever 30 is received in the spherical depression 50 in end Wall 4S of the bellows. Rivet 42 engages plunger 28 and maintains it in an upper position. With lever 30 in the position illustrated in FI l, cam 4o is in the at rest position.

Upon rotation of cam 4t) in a clockwise direction, as shown in FIG. 3, lever 30 pivots counterclocliwise about pin 34, and head 44 of rivet 42 is carried downwardly compressing bellows 46. As bellows 46 is compressed, the air `or other fluid in 4the interior thereof is expelled through threaded opening S4 between the threads, through opening 56 in wall `12, and out through filter element 64. When cam 40 returns to the at rest position of FIG. l, the compress-ive `force on bellows 46 is released. When the force of lever 30 is released from bellows 46, the inherent bias of the bellows causes it to extend to its normal position or size shown in FIG. 1. Extension of the bellows causes air or other fluid to be drawn through filter element 64, opening 56 and between threaded opening 54 to the interior of the bellows. The rate at which fluid flows through the -iilter element and openings determines the time interval at which bellows 46 will expand to its fully extended position of FIG. l to reposition plunger 28 in its original position. Accordingly, if screw 513 is rotated counterclock- Wise, the density of filter element 64 decreases, and the rate of iluid ow through the lter increases to thereby reduce the time ylapse required for bellows 46 to return to its normal size. Conversely, clockwise rotation of screw 58 increases the density of lter ele-ment 64 and accordingily, increases the resistance of the lter element to iluid flow, which in turn increases the time interval required lfor bellows 46 to extend from the position shown in FIG. 3 to its normal position as shown in FlG. 1.

The above described device is simple in construction `and provides a novel means for adjusting the time delay interval desired between operations of a particular control apparatus.

While a specific construction has been described and illustrated for purposes of illustration, it will be under- :stood `by those skilled in the a-rt that various modifications can be made Without departing from the scope of the appended claims.

What I claim is:

1. A time delay actuator comprising a support means hav-ing an opening, a resilient hollow capsule having a threaded opening at one end, said capsule being mounted on said support means with `said threaded opening in coaxial alignment with the opening in said capsule thereby forming a path of uid ilow to .and from the interior of the capsule, a screw loosely threaded in the opening in said capsule and having a ange portion spaced from said support means on the side opposite that of the capsule, a porous compressible filter means disposed between said support means and said ange portion of the sc-rew in the path of ilow to and from the interior of the capsule, said -screw securing the capsule to said support means while being rotatable in said threaded opening in the capsule for selectively increasing or decreasing the density of the iilter means, and means `for contracting said capsule, said capsule thereafter expanding at a rate determined by the flow of luid through said lter meansl ing element, a thread-ed opening in .said one end of saidl bellows coaxially disposed with the opening in said other wall for uid flow to and from the linterior of said bellows -upon expansion and contraction thereof, a screw loosely received in said threaded opening and having an enla-rged head disposed on the opposite side of said other wall from said bellows, a porous compressible tilt-er element having a central portion conned between s-aid enlarged head and said support and an uncontined peripheral portion projecting beyond said enlarged head, the density of said conned central portion of said filter element being .increased and decreased by rotation of said screw while said screw -at the same time Vserving to secure the bellows to said other IWall and means for pivotally rotating said lever to contract said bellows, said bellows thereafter expanding at a lr-ate determined by the rate of fluid ilow through said filter element and said thread-ed opening to again move said actuating element into engagement with sai-d plunger to actuate said switch.

References Cited by the Examiner UNTED STATES PATENTS 942,623 l12/09 Dixon 20G-34 1,942,040 1/34 Wolff 18S-94 2,689,916 9/54 Lohman et al 188-94 2,881,285 4/59 Bank ZOO-97 2,899,523 8/59 Flatet etal. .20034 2,976,961 3/61 Mead 188-97 BERNARD A. GILHEANY, Primary Examiner.

WALTER STOLWEIN, Examiner. 

1. A TIME DELAY ACTUATOR COMPRISING A SUPPORT MEANS HAVING AN OPENING, A RESILIENT HOLLOW CAPSULE HAVING A THREADED OPENING AT ONE END, SAID CAPSULE BEING MOUNTED ON SAID SUPPORT MEANS WITH SAID THREADED OPENING IN COAXIAL ALIGNMENT WITH THE OPENING IN SAID CAPSULE THEREBY FORMING A PATH OF FLUID FLOW TO AND FROM THE INTERIOR OF THE CAPSULE, A SCREW LOOSELY THREADED IN THE OPENING IN SAID CAPSULE AND HAVING A FLANGE PORTION SPACED FROM SAID SUPPORT MEANS ON THE SIDE OPPOSITE THAT OF THE CAPSULE, A POROUS COMPRESSIBLE FILTER MEANS DISPOSED BETWEEN SAID SUPPORT MEANS AND SAID FLANGE PORTION OF THE SCREW IN THE PATH OF FLOW TO AND FROM THE INTERIOR OF THE CAPSULE, SAID 